1 files changed, 136 insertions, 0 deletions
diff --git a/libpkgconf/cache.c b/libpkgconf/cache.c
new file mode 100644
index 0000000..986eba5
--- /dev/null
+++ b/libpkgconf/cache.c
@@ -0,0 +1,136 @@
+/*
+ * cache.c
+ * package object cache
+ *
+ * Copyright (c) 2013 pkgconf authors (see AUTHORS).
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <libpkgconf/libpkgconf.h>
+
+/*
+ * !doc
+ *
+ * libpkgconf `cache` module
+ * =========================
+ *
+ * The libpkgconf `cache` module manages a package/module object cache, allowing it to
+ * avoid loading duplicate copies of a package/module.
+ *
+ * A cache is tied to a specific pkgconf client object, so package objects should not
+ * be shared across threads.
+ */
+
+/*
+ * !doc
+ *
+ * .. c:function:: pkgconf_pkg_t *pkgconf_cache_lookup(const pkgconf_client_t *client, const char *id)
+ *
+ *    Looks up a package in the cache given an `id` atom,
+ *    such as ``gtk+-3.0`` and returns the already loaded version
+ *    if present.
+ *
+ *    :param pkgconf_client_t* client: The client object to access.
+ *    :param char* id: The package atom to look up in the client object's cache.
+ *    :return: A package object if present, else ``NULL``.
+ *    :rtype: pkgconf_pkg_t *
+ */
+pkgconf_pkg_t *
+pkgconf_cache_lookup(const pkgconf_client_t *client, const char *id)
+{
+	pkgconf_node_t *node;
+
+	PKGCONF_FOREACH_LIST_ENTRY(client->pkg_cache.head, node)
+	{
+		pkgconf_pkg_t *pkg = node->data;
+
+		if (!strcmp(pkg->id, id))
+		{
+			PKGCONF_TRACE(client, "found: %s @%p", id, pkg);
+			return pkgconf_pkg_ref(client, pkg);
+		}
+	}
+
+	PKGCONF_TRACE(client, "miss: %s", id);
+	return NULL;
+}
+
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_cache_add(pkgconf_client_t *client, pkgconf_pkg_t *pkg)
+ *
+ *    Adds an entry for the package to the package cache.
+ *    The cache entry must be removed if the package is freed.
+ *
+ *    :param pkgconf_client_t* client: The client object to modify.
+ *    :param pkgconf_pkg_t* pkg: The package object to add to the client object's cache.
+ *    :return: nothing
+ */
+void
+pkgconf_cache_add(pkgconf_client_t *client, pkgconf_pkg_t *pkg)
+{
+	if (pkg == NULL)
+		return;
+
+	pkgconf_pkg_ref(client, pkg);
+	pkgconf_node_insert(&pkg->cache_iter, pkg, &client->pkg_cache);
+
+	PKGCONF_TRACE(client, "added @%p to cache", pkg);
+}
+
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_cache_remove(pkgconf_client_t *client, pkgconf_pkg_t *pkg)
+ *
+ *    Deletes a package from the client object's package cache.
+ *
+ *    :param pkgconf_client_t* client: The client object to modify.
+ *    :param pkgconf_pkg_t* pkg: The package object to remove from the client object's cache.
+ *    :return: nothing
+ */
+void
+pkgconf_cache_remove(pkgconf_client_t *client, pkgconf_pkg_t *pkg)
+{
+	if (pkg == NULL)
+		return;
+
+	PKGCONF_TRACE(client, "removed @%p from cache", pkg);
+
+	pkgconf_node_delete(&pkg->cache_iter, &client->pkg_cache);
+}
+
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_cache_free(pkgconf_client_t *client)
+ *
+ *    Releases all resources related to a client object's package cache.
+ *    This function should only be called to clear a client object's package cache,
+ *    as it may release any package in the cache.
+ *
+ *    :param pkgconf_client_t* client: The client object to modify.
+ */
+void
+pkgconf_cache_free(pkgconf_client_t *client)
+{
+	pkgconf_node_t *iter, *iter2;
+
+	PKGCONF_FOREACH_LIST_ENTRY_SAFE(client->pkg_cache.head, iter2, iter)
+	{
+		pkgconf_pkg_t *pkg = iter->data;
+		pkgconf_pkg_free(client, pkg);
+	}
+
+	memset(&client->pkg_cache, 0, sizeof client->pkg_cache);
+
+	PKGCONF_TRACE(client, "cleared package cache");
+}